Perhaps you should try some spelling variations:
health impedance » health importance, health temperance, head impedance
incidence nets » incidence les, incidence costs, incidence depth
incidence des » incidences des, incidence de, incidence les

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (( health ((incidence nets) OR (incidence des)) synthesis report ) OR ( health impedance ((network synthesis) OR (network systems)) report )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( health ((incidence nets) OR (incidence des)) synthesis report ) or ( health impedance ((network synthesis) or (network systems)) report ))".
• Adding a wildcard symbol may retrieve word variants: (( health ((incidence nets) OR (incidence des)) synthesis report ) or ( health impedance ((network synthesis) or (network systems)) report ))*.